December 2009

- The big question is how Microsoft will fare if Chrome OS and Apple's rumored "iTablet" (whatever they finally call it) become popular. Of course , that question is predicated upon the concept of "apps in the cloud" actually being successful - some stridently insist that no one will buy these things at all. There are two prongs to the "this won't fly" argument: one is that few people will give up "fat" computing, and the other is that people will not embrace this because of concerns about privacy, security and app/vendor lock-in.

- Mint works by you allowing it to access your bank and credit card accounts. That right there is enough to turn off most people, but as they explain at their privacy faq, money can't be transferred with Mint and all they need is your email - no names or other personally identifiable information. They argue that they actually increase your security by being able to notify you of any unusual activity in your various accounts.

- Suppose you were writing a commenting system for a website and you wanted to check user input against a list of words that might indicate spam. You'd want the list of suspicious words in a file and you'd run through that list. An easy way to do that in Perl is to use Perl's "grep" command.

- In part 1, I talked about code to read a list of spammish words from a file and look for those words in comment posts. Commenters pointed out that spammers will obfuscate words with dashes, spaces, bizarre spellings and so on, making it very difficult to catch these programmatically. That's true, but there's more to the story.

- In the previous posts in this series, I've said that spammers habits allow us to detect their attempts to leave inappropriate comments. I use these techniques here and am able to send most spam comments directly to the bit-bucket without ever having to examine them myself. When I suspect spam but am not sure, I just send the comment to moderation. In practice, very few spam attempts get by the automatic filters.

- We looked at both System V and BSD methods; until fairly recently that would have been the end of the discussion: if you were running Unix/Linux, your system used one or the other of these. Not everyone was satisfied, though

- The rc.d system is used on NetBSD, FreeBSD and DragonFly (and possibly a few other systems) to launch daemon processes when the system goes multiuser and terminate them properly at system shut down. In the interests of brevity this article will not examine the system comprehensively: rather, this guide is focussed solely on adding new scripts to control additional daemons or perform other tasks at start up and shut down. Even with this narrow focus I will not attempt a comprehensive treatment, but this guide should suffice for most common tasks and still remain brief enough to read when you actually need to write such a script.

- I wrote Automating Program Startup almost 10 years ago. A lot has changed since then and I realized that this has actually become a fairly complicated subject when I tried to answer a forum post that simply asked about starting an arbitrary service. Because that poster used "httpd" as an example and was using a Fedora system, several answers mentioned "chkconfig". That's the right answer if we are specifically asking about httpd on a Fedora system, but it's not the right answer for any arbitrary service on any arbitrary Unix or Linux system.